Much has been made, repeatedly, about Donald Trump's tax returns and the reasons behind his decision to not release them yet.

His assertions of not releasing the returns due to an IRS audit have been dismissed repeatedly, too. The speculation rages on that it's a combination of not being worth as much as Trump says he is and an extremely low tax rate. According to a Politico story, Trump's tax returns would spell out accounting practices that reveal:

Trump's businesses don't produce as much net income

Trump assigns himself a net worth that's impossible to verify

He's selling assets and increasing debt, suggesting cash flow issues

"Trump has a tendency to value his brand at a very high amount but these are usually intangible valuations just pulled out of thin air," Steve Stanganelli, a certified financial planner told Politico. "And he appears to be reporting gross revenue. There is a huge difference between that and net income."

Trump and his camp consistently report a net worth north of $10 billion with income at over $550 million. Fortune Magazine puts his net worth at almost $4 billion, while a 2005 book put Trump's net worth at $150 million to $250 million, Politico reported.

A central issue is how Trump assigns value to his assets, specifically his many golf courses and resorts, about 14 of which get a Trump valuation of north of $600 million, Politico reported.

"Unless we really know what the income and expenses for the clubs are, it's impossible to even guess at what the value would be," Larry Hirsh, a founder of the Society of Golf Appraisers told Politico. "He’s a classic example of a guy that, when he wants to get a loan or tell you how wealthy he is, he'll tell you something is worth a bazillion dollars. But when he wants to get taxes reduced he'll tell you it's worth $2.95."